Method of pumping oil



Sept 5 1944 D. s. KAUFMAN 2,357,660

METHOD OF PUMPING OIL File'd'May 2s, 1943 SEPARATING 72 DAVID S. KAUFMAN 'v Patented Sept. 5, 1944 METHOD F PUMPING OIL l Davids. Kaufman, Port Arthur, Tex., assigner to Texaco Development Corporation, New York,

N. Y., a corporation of Delaware Application May 28, 1943, Serial No. 488,934

7 Claims. l(Cl. 10S-46) 'Ihis invention relates to a method of producing petroleum oils, and more particularly to a method of pumping such oils from underground formations by means of hydraulic pumps.

Hydraulic pumps have certain advantages over mechanical pumps when used for pumping oil wells, and their use has tended to increase during the last few years. rl'hese pumps are usually actuated by a relatively clean portion of crude oil being produced from the pumping well or nearby wells, the oil being forced down a power tubing under relatively high pressure. This power oil passes through the pump and then is exhausted into the oil being produced from the well. power oil, therefore; becomes a part of the production oil, and new portions are continuously obtained for use in further pumping.

'I'he chief difliculties with hydraulic pumps have been experienced when these pumps are employed for pumping oil from formations containing crude oil tending to deposit paraflin. These difliculties are encountered in the power tubingand also in thetubing carrying the production oil. It; has

been found that although the oil to be used as the power oil may be filtered before use, it still retains precipitableparaflin. This parainn deposits in the relatively'small diameter tubing carrying the power oil. As a result, the power required for applyingl adequate pressure to the oil is increased, and periodic shutdowns of the well and cleanings of the tubing are required.

The deposition of paraffin in the power tubing is especially heavy during the warm months of the year. This is thought to be due to the fact that when the oil at the surface is maintained at a relatively high temperature, light hydrocarbons are evolved and the loss of these hydrocarbons decreases the solubilizing properties of the remaining oil for paraffin. On the other hand, the Aproblems of parafn deposition in the ow tubing are especially troublesome during the colder months. In this case, it is thought the parain precipitates because the oil is cooled to a relatively low temperature in the course of its iiow up the tubing. To keep the ow tubing of a Well producing oil tending to deposit parallin in condition to permit flow of oil, it has been necessary to resort to the familiar expensive methods of parailin removal.

The present invention lis `concerned with a method of operating hydraulic pumps of the type described above, whereby diiculties with respect to parailin deposition may bereduced or eliminated. The invention resides particularlv in ,the

use of a novel type of power fluid for actuating the pumps. e

In order that the invention may be understood more fully, reference should be had to the drawing in which Figure 1 is a side elevation, partly in sectionjof an oil well equipped with a hydraulic pump. 'I'his gure also shows in diagrammatic form the flow of fluids at the surface employed in the operation of the present method. Figure 2 is an enlarged vertical sectional view of= the power cylinder of a familiar type of hydraulic pump employed in oil wells.

Referring to Figure 1, a well is shown equipped with a casing I0 suspendedfrom a casing head I2 and having perforations I I opposite the formation. A ow tubing I4 is disposed within the casing. This flow tubing is in two sections, Ida and Idb, -the two sections being connected by means of a coupling I6. rAt the lower end of the section I 4b is a shoe I8 containing passages 22 and 24. A tubing 26 having a threaded engagement with coupling I6 denes an annular space with the external'suriace of section Mb. The bottom end of the tubing 2B is closed by means of a closure 28. Rigidity of construction is provided by means of a bolt 30 which links closure 28 and shoe I8. 4The tubing 2B is provided with perforations 32 at its upper end.

The pumping unit is represented generally at 34. This unit may be of any familiar type and comprises in general a power cylinder, wherein a piston is caused to reciprocate by the power oil, and a pump or production cylinder, wherein a piston actuated by the power piston operates to pump oil from the well. A typical power cylinder is shown more in detail in Figure 2. Leading from the production unit to the surface is a power tubing 36 which is connected to a power fluid line 38. Line 40 leads from the top of the casing head for the purpose of conducting the production oil from the well.

When pumping a well using a. hydraulic pump of this general type, the pump is so disposed in the well that the crude oil rises atleast to the perforations 32 in tubing 26. The oil passes through these perforations and enters the annular space between tubing 26 and section I4b of the tubing I4. From this space, it flows through passages 22 and 24 into the production unit of the pump. It is owed from the pump and up tubing I4 to pipe 40.

The operation .of the pump will be understood by reference to Figure 2. In this figure, where corresponding parts appear, they bear the same The device disclosed in this figure may be termed a hydraulic engine, and comprises, in general, a cylinder 42, a power piston 44, a valve 46, and ports and channels adapted to regulate the flow of the power uuid. The motion of the piston 44 is transmitted to a similar piston in the production cylinder, not shown, by means of a. rod 48.

The power piston and valve are shown in the downward position. In this position, the power fluid flowing through power tubing 36 passes through the channel 50 to the upper end of the power cylinder, thus forcing the piston A'41! downward. In this position, the lower endof the power cylinder is open to exhaust through `the channel 52, the exhausted oil flowing into tubing It, not shown in this figure. As the piston reaches the end of the downward stroke, grooves 54 in valve rod 56 permit the passage of the power fluid through ports 58 and into the space 60 below the valve body.. Because the bottom end area of the valve is greater than the upper end area, the oil entering below the valve causes the Valve to move upward. When the valve reaches its top position, the channel 50 isl open to exhaust through the annular space 62, and the channel 64 is brought into alignment with channel 52, which causes the power iluid to enter the space beneath the piston and forces the piston to move upward. When the piston has reached its full upward position, a groove 6B in valve rod 56 is brought into alignment with a port 58 and a channel 68 leading to the exhaust. Thus, when the piston has reached its full upward position, the power oil below the valve body will be exhausted and the cycle repeated.

In accordance with the present invention,

crude oil tending to deposit paran is pumped from an underground formation by a method comprising using a hydraulic pump of the type described above, and actuating the pump by means of a power liquid comprising a substantial aqueous phase. The power liquid may be water alone, but it is preferred to employ water containing a suilicient amount of a demulsifying agent to yreduce or prevent emulsification of the water with the production oil. In an important embodiment of the invention, the power liquid comprises a mixture of Water and a hydrocarbon oil, the mixture preferably also containing a demulsifying agent.

By using a power liquid of the class described above, diiiiculties with respect to parain deposition in the power tubing are eliminated. Further, depending upon the amount of the power liquid used and the characteristics of the production oil, the introduction of Water into the kproduction oil tends to reduce the deposition of parain in the ilow tubing. Moreover, when it is particularly desired to control the deposition of paraiiin in the ow tubing, the amount of water introduced into this tubing is adjusted so as to be at least sufficient to prevent or reduce such deposition.

Although the invention in its broader aspects includes'the useof water alone as the power liquid, I prefer to employ an aqueous liquid containing other materials, as explained below. A crude oil which-tends to deposit paraffin often contains constituents which reduce the emulsifying characteristics of the oil; but in some cases, when using water as the power liquid, there is a tendency forl the water to form an emulsion with the production oil. By incorporating in the These materials are employed in the form of their salts, such as their ammonium salts.

An especially important embodiment of the present invention comprises the use of a mixture 'of a hydrocarbon oil and water as the power liquid. A mixed liquid of this type may be made so as to besubstantiallyfree from a tendency to deposit paraffin, and yet to possess desirable lubricating properties. These properties are of advantage when the mixed liquid comes in contact with the engine piston and valve. Since as littleas one per cent by volume of oil in the water is suiiicient to impart desirable lubricating properties thereto, it is possible to use relatively refined oils in the operation. However, for reasons of economy and convenience, it is generally preferred to use a mixture of water and crude oil, which may be the'production oil or oil produced from a nearby well. Mixed liquids containing from about 15 to 99 per cent water and from about 85 to l per cent crude oil by volume are satisfactory, both from thestandpoint of paraiiin deposition and accomplishing effective lubrication of the moving parts of the hydraulic pump. When using a mixed liquid of this type, it is preferred also to include in the mixture a small amount of a suitable demulsifying agent, such as disclosed above. It is not desirable or necessary that the mixed liquid be in the form of a stable emulsion, and, cf course, emulsication of the water of the mixed liquid with the v production oil is undesirable.

When using any particular hydraulic pump there is a deiinite ratio between the amount of power liquid and the amount of new production. This ratio is generally about 1:1 by volume. Since it has been found that where the well production contains at least l5 per cent water, paraflin deposition is decreased, I prefer to employ a power liquid containing an amount of water equal to at least about 20 per cent of the oil being produced. The type of power liquid to be used, therefore, will depend upon the specific characteristics of the oil'and also in many cases upon the temperature at the surface. It has been pointed out that paramn deposition in the ow tubing is greater in cold Weather. Accordingly, it is important at such times to employ enough water in the power liquid to yield a mixed liquid at 'the well head containing at least 15 per cent water. When the well is producing some water, this water should be taken into account in determining the minimum amount required in the power liquid.

Therefore, to reduce parafin deposition in both the power tubing and the ow tubing in the case where the ratio between the power liquid and production oil is 1:1 and substantially no water is being produced, the power liquid should be composed of at least 30 per cent water, and preferably would be composed of at least 40 per cent water.

The operation of the method will be mademore clear by reference to Figure 1. In this case, a

' erally at 12.

2,357,eoo

mixture of water and a crude oil in about equal proportions by volume is employed as the power liquid. This mixture is raised by means of vpump 10 to a desired pressure which may be of the order of 1,000 to 3,000 pounds per square inch, depending' upon underground conditions, and is .passed through valved line 38 to the well. The

liquid flows through line 36 and actuates the engine inthe manner before described. The production oil together with the exhausted power liquid, passes up flow tubing I4 and. from the well through valved line 40. This line conducts the mixture into a separating system indicated gen- In this system, which may be of any conventional type, the Water is separated from the oil and is removed through valved line .14 which leads to the suction side of pump 10. Make-up water may be introduced through a valved line 1G. separating system through valved line 18 and is combined with the water flowing in line 14. A suitable demulsifying agent may be added to water through valved line 80. Production oil is removed from the'separating system through valved line 82 and. passed to storage.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In a method of pumping crude oil tending to deposit paraflin from an underground formation wherein a hydraulic pump is employed, a power liquid underpressure is forced down a power tubing to actuatev the pump, and the exhaustpower liquidis mixed with the production Clean oil is removed from the which the power liquid is composed substantially of water and a hydrocarbon oil and comprises at least 15 per cent water and at least one per cent hydrocarbon oil by volume.

5. In a method of pumping crude oil tending to deposit paraiiin from an underground formation wherein a hydraulic pump is employed, a power liquid under pressure is forced down a power tubing to actuate the pump, the exhaust 29 power liquid is mixed with the production oil in a ow tubing, and the volume ratio of power liquid to production oil is about 1:1, the improvement which comprises actuating the pump by means of a power liquid comprising at least 30 g5 per cent water by volume, whereby deposition of paraffin is reduced in the power tubing and in the flow tubing.

o 6. A method in accordance with claim 5 in which said power liquid also comprises at least 30 one per cent by volume of a hydrocarbon oil produced from said underground formation.

7. A method in accordance with claim 5 ln which said power liquid also comprises a hydrocarbon oil and a demulsifying agent, said power 35 liquid comprising at least one per cent by volume of said hydrocarbon oil.

v DAVID S. KAUFMAN. 

